Called a 'smooth edge' that cuts the seal of the can from the side, rather than through the top. It doesn't have the risk of metal particles into the can, or sharp edges left exposed. OXO Good Grips has one that gets pretty high praises for its' ease of use. It can take a few cans to get the idea of how it works, since it's 'different', but once you wrap your head around it, you'll be hooked.

Hope this helps.